Air precleaner for centrifugally ejecting heavier than air particulate debris from an air stream

ABSTRACT

An air precleaner and method for centrifugally ejecting heavier-than-air particulate debris from an air stream utilizes a circular separator chamber formed with a toroidal dome for smooth airflow transition of the vortex airflow moving through the separator chamber in a cyclonic pattern upwardly from an inlet in a base of the precleaner past a debris ejection duct where it is folded over by the toroidal dome for whirlpooling down to an outlet in the base radially inwardly of and through the upwardly moving vortex airflow. The area for the airflow in the separator chamber progressively decreases linearly to increase the speed of the airflow in the chamber. A particle accelerator assembly includes a plurality of appendages that arc back from a central hub in a swept-back attitude relative to a direction of the vortex airflow. The particle accelerator assembly is rotatably powered at a speed in excess of the speed of the incoming vortex airflow for increasing the speed thereof in interaction of a portion of the appendages with the higher speed outgoing airflow. The air precleaner, which can be used for internal combustion engines, for example, dramatically improves the removal of heavier-than-air particles across a broad spectrum of intake air demand. It maximizes the use of centrifugal force while minimizing airflow restriction, offering a flat performance curve over the entire airflow range.

FIELD OF THE INVENTION

The present invention relates to an improved air precleaner and methodfor centrifugally ejecting heavier-than-air particulate debris from anair stream which is drawn through the air precleaner for use in anapparatus such as an internal combustion engine, a ventilation system, acooling fan, or an air compressor.

BACKGROUND AND SUMMARY OF THE INVENTION

Air precleaners that separate heavier-than-air particles from the airused in combustion type engines are known. All of these known airprecleaners are functional, but do not address the needs of currentcombustion engine designs for extremely low initial restriction and highparticle separating efficiency over the broad airflow range with whichthey are used.

The following is a list of U.S. pat. nos. relating to air cleaningdevices:

U.S. Pat. Nos. 2,193,479 2,304,778 2,417,130 2,973,830 3,552,1023,670,480 3,740,932 3,973,937 4,138,761 4,197,102 4,201,557 4,547,2075,022,903

An object of the present invention is to provide an improved airprecleaner and method for centrifugally ejecting heavier-than-airparticulate debris from an air stream which overcome the aforementioneddisadvantages of the known air precleaners. More particularly, an objectof the present invention is to provide an improved air precleaner andmethod which meet or exceed the requirements for use of the airprecleaner in connection with diesel engines, offering significantimprovements in debris removal with minimal impact on intake airflow ascompared with conventional air precleaners. A further object of theinvention is to provide an improved air precleaner which can also beadapted for use on other systems that require ambient air at allenvironmental and altitudinal applications.

These and other objects of the invention are attained by the airprecleaner of the invention, which according to a disclosed preferredembodiment comprises a base; a circular separator chamber connected tothe base and including an inner wall with a debris ejection ducttherein, and a particle accelerator assembly rotatably mounted in theseparator chamber. The base has an inlet for the passage of debris ladenair into the air precleaner, a plurality of air inlet vanes angledupwardly with respect to a longitudinal axis of the air precleaner fordirecting incoming debris laden air into the circular separator chamberas a vortex airflow, and an outlet for the passage of air from the airprecleaner after the air has moved through the circular separatorchamber for centrifugally removing heavier-than-air particulate debristherefrom by way of the debris ejection duct.

The circular separator chamber of the air precleaner is formed with atoroidal dome in the disclosed embodiment for smooth airflow transitionof the vortex airflow moving through the separator chamber in a cyclonicpattern upwardly from the inlet past the debris ejection duct where itis folded over by the toroidal dome for whirlpooling down to the outletradially inwardly of and through the upwardly moving vortex airflow inthe chamber. The inside surface of the separator chamber is configuredto minimize resistance to the airflow vortex while directing the airflowvortex to change directions, enter the air outlet passageway in thebase, and enter into the intake duct of the associated device such as aninternal combustion engine. The air inlet vanes, base and cylindricaltoroidal dome separator chamber are also configured to direct the vortexairflow with a minimum of turbulence and airflow restriction.

The toroidal dome of the separator chamber is formed by a circulartoroidal arch at an upper end of the separator chamber in theillustrated embodiment. The inner wall of the separator chamber, as seenin a cross section thereof along a longitudinal axis of the airprecleaner, slopes inwardly in the direction of the toroidal dome todecrease the cross sectional area of the flow path for the vortexairflow moving through the separator chamber. In the disclosedembodiment, the shape of the separator chamber provides a linearreduction in cross sectional area of this flow path thereby increasingthe velocity of the vortex airflow in the chamber and keeping debris inthe air circulating around the inner wall of the chamber for ejectionthrough the debris ejection duct.

According to the preferred embodiment, the debris ejection duct extendsupwardly along the inner wall of the separator chamber between the airinlet and the toroidal dome. The open area of the debris ejection ductis larger at a lower end thereof and decreases from the lower end to theupper end.

The particle accelerator assembly of the air precleaner includes acentral hub and a plurality of curved appendages that arc back from thecentral hub in a swept-back attitude relative to the direction of thevortex airflow coming off the upwardly angled air inlet vanes. A curvedarea of the appendages extends downwardly to a passageway of the airoutlet of the base. The curved area is cupped in the direction of theairflow vortex in the air outlet passageway for rotationally poweringthe particle accelerator assembly at a speed greater than the rotationalspeed of the incoming vortex airflow. This configuration of theappendages produces an outward velocity vector to any air or debris thatis impacted by the appendages, thus encouraging ejection from the debrisejection duct.

The particle accelerator assembly further includes a center shaftconnected to the central hub. The assembly is rotatably mounted in theseparator chamber by way of the center shaft which is rotatablysupported by a bearing assembly in an upper end of the separatorchamber. The central hub has an outer configuration which forms a smoothtransition from a downward arch of the circular toroidal dome of theseparator chamber to the bottom of the central hub which ends as arounded tipped cone centered over the air outlet in the base of the airprecleaner. A labyrinth seal is provided between adjacent ends of thecentral hub of the particle accelerator assembly and the downward archof the circular toroidal dome of the separator chamber in the vicinityof the smooth transition from the downward arch to the central hub. Thelabyrinth seal discourages debris migration from the separator chamberto the bearing assembly. This arrangement of the particle acceleratorassembly within the separator chamber allows the air precleaner todirect the airflow vortex with a minimum of turbulence and resistance.

The radial outer ends of the appendages of the particle acceleratorassembly extend vertically and are contoured to match an inward slope ofthe circular toroidal dome separator chamber with an equal distancealong the entire leading edge of the vertically extending outer ends ofthe appendages to the debris ejection duct. The vertically extendingouter ends of the appendages are wider at their bottom end and narrow inthe direction of their top end. Each of the vertically extending outerends of the appendages have a plurality of outwardly directed strakesformed thereon for entrapping and directing debris into the debrisejection duct. Each of the air inlet vanes is also provided withdirectional strakes on its windward side for directing the airflow as itpasses over the air inlet vanes. The appendages also each have strakesformed into the top and bottom of a leading edge thereof for entrapmentof air borne debris, directing the debris down the length of theappendage and depositing the debris in the airflow vortex circulatingaround the inner wall of the circular toroidal dome separator chamber.As noted above, the improved air precleaner of the invention is poweredby the air that is pulled through the inlet thereof and operates onfractional horsepower, resulting in minimal air restriction for maximumparticle ejection efficiency.

The debris ejection duct in the wall of the separator chamber extendsupwardly at a 90° angle along the inward sloping surface, stopping atthe top of the circular toroidal dome separator chamber. The ejectionduct is in effect an air scoop that extends into the outermost area ofthe airflow vortex such that it will eject debris and a small quantityof vortex air from the separator chamber. The debris ejection duct ispositioned near normal to the airflow vortex, thus presenting severalopportunities for debris ejection while the airflow vortex passes overthe air scoop multiple times. The debris ejection duct is tapered fromthe largest opening at the lower end thereof, to the smallest open areaat the top of the duct. This encourages the ejection of debris andminimizes loss of air from the airflow vortex.

The inner wall of the separator chamber in the disclosed embodiment isconfigured with three circumferential strakes. One strake is located atthe bottom of the debris ejection duct, one is in the middle, and one isat the top. These strakes are effective to trap debris and direct itinto the debris ejection duct while minimizing any effect on the airflowvortex.

A method of the invention for moving air through an air precleaner forcentrifugally ejecting heavier-than-air particulate debris from themoving air comprises drawing debris laden air into the air precleaner,directing the air drawn into the air precleaner into a vortex flowwithin the air precleaner, increasing the velocity of the vortex flowwithin the air precleaner for centrifugally ejecting heavier-than-airparticulate debris therefrom, and smoothly folding over the vortex flowat one end of the air precleaner by interacting the vortex flow with atoroidal dome of the air precleaner for whirlpooling the moving air backthrough the vortex flow inwardly thereof to an air outlet of the airprecleaner. As noted above, the step of increasing the velocity of thevortex flow within the air precleaner includes moving the vortex flowthrough a passage in the air precleaner whose cross sectional areaslinearly decreases. The velocity of the vortex flow in the air cleaneris also increased by interaction of the vortex airflow with theappendages of the particle accelerator assembly which move through theair at speeds greater than the incoming air.

These and other objects, features and advantages of the presentinvention will become more apparent from the following description of apreferred embodiment in accordance with the invention when taken inconnection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view of the air precleaner of the presentinvention.

FIG. 1A is a sectional view through an appendage of the particleaccelerator assembly in FIG. 1 taken along the line I--I;

FIG. 2 is a bottom view of the cylindrical base assembly and FIG. 2A isa sectional view of the directional strake of an upwardly angled airinlet vane of the present invention taken along the line II--II in FIG.2;

FIG. 3 is a side sectional view of the cylindrical base assembly of thepresent invention;

FIG. 4 is a top view of the particle accelerator assembly of the presentinvention;

FIG. 5 is a side view of the particle accelerator assembly of thepresent invention with a portion cut away to expose the male labyrinthseal lip;

FIG. 6 is a bottom view of the circular toroidal dome separator chamberof the present invention;

FIG. 7 is a top view of the particle accelerator assembly and thecylindrical base assembly of the present invention;

FIG. 8 is a side sectional view of the air precleaner of the presentinvention with a portion of the particle accelerator assembly cut away;

FIGS. 9A and 9B are two vertical sections of the circular toroidal domeseparator chamber of the present invention taken along lines A--A andB--B in FIG. 10, respectively;

FIG. 10 is a side view of the air precleaner of the present invention;

FIG. 11 is a side sectional view of the air precleaner of the presentinvention with a portion of the particle accelerator assembly cut awayto show the cross section area of the precleaner; and

FIG. 12 is graph illustrating the high level of performance of the airprecleaner of the invention over the broad range of airflow ratesthrough the air precleaner to an internal combustion engine expressed asa function of percentage of particles of a certain size removed from theincoming air by the air precleaner.

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENT

With the reference to the drawings, FIGS. 1-11 show various views of theair precleaner of the present invention at 1. The air precleaner 1 iscomprised of a cylindrical base assembly 33 and has an air inletpassageway 2, an air outlet passageway 29, a circular toroidal domeseparator chamber 5 attached to the top of the cylindrical base assembly33 and having a debris ejection duct 25, and a particle acceleratorassembly 16 that is rotatably mounted to the center of the circulartoroidal dome separator chamber 5. The air precleaner 1 is a device usedfor separating debris from the air in all environments and all altitudeconditions.

The cylindrical base assembly 33 is formed in a single piece to includean outer circumferential partition 40 connected to an innercircumferential partition 32 by multiple upwards angled air inlet vanes34, and the inner circumferential partition 32 forms the air outletpassageway 29 having multiple stop tabs 30, slots 46 and leading edgechamber 31. According to the orientation as is shown in the figures, theouter circumferential partition 40 has a top 41 and a bottom 42; theinner circumferential partition 32 has a top 43 and a bottom 44.

At numerous places around the top edge of the outer circumferentialpartition 40 are the male interlocking connector joints 35 that mate tothe numerous female interlocking connector joints 4 to form theinterlocking connector joints 51 attached to the bottom edge of thecircular toroidal dome separator chamber 5.

In the orientation shown in FIG. 2, air enters the air precleaner 1through the upwardly angled air inlet vanes 34. Each upwardly angledinlet vane 34 is positioned at an offset angle relative to thelongitudinal center axis C--C, FIG. 1,of the air outlet passageway 29and air precleaner 1 which is encircled by the air inlet passageway 2.The leading edges 47 of the upwardly angled air inlet vanes 34 arecurved downward, reducing the airflow angle of incidence and thusreducing the airflow drag. Each upwardly angled air inlet vane 34 hasnumerous directional strakes 61 attached to its windwards, e.g. bottom,side 50 starting at the leading edge 49 of the directional strake 61 onthe leading edge 47 of the upwardly angled air inlet vane 34 andextending upwardly to the trailing edge 48 of the upwardly angled airinlet vane 34. These directional strakes 61, along with the offsetupwardly angled air inlet vanes 34, contribute to directing the airflowas it passes over the upwardly angled air inlet vanes 34. This airflowmanagement is crucial to the operating efficiency of the air precleaner1.

In the orientation shown in FIG. 1, air and debris must be moved to theinside of the circular toroidal dome separator chamber 5 and out thedebris ejection duct 25 to be removed from the airflow vortex.Centrifugal force and airflow management are the principal forces toperform this task.

In the orientation shown in FIGS. 6 and 7, as the airflow leaves eachupwardly angled air inlet vane 34 in a vortex flow pattern and comes incontact with the particle accelerator assembly 16, the velocity of theair and debris is increased and vented outwards towards the inside ofthe circular toroidal dome separator chamber 5. In the orientation shownin FIGS. 1, 4, 5, 6 and 7 the appendages of the particle acceleratorassembly 16 are curved at an arc extending from the central hub 36,resulting in a swept-back attitude relative to the direction of thevortex airflow coming off the upwardly angled air inlet vanes 34,reducing airflow turbulence and causing increased airflow rotationalvelocity and thus centrifugal acceleration of debris along the curvedappendages leading edge 3 and vertical appendage 19, producing anoutward velocity vector to the airflow and debris, encouraging ejectionfrom the circular toroidal dome separator chamber 5 through the debrisejection duct 25. The trailing edge of the particle acceleratorappendage 18, the trailing edge of the vertical appendage 45, and thetrailing bottom of the vertical appendage 20 are streamlined to minimizeairflow turbulence. The curved area of the appendages 17 that extendsdownward into the air outlet passageway 29 is cupped into the directionof the airflow vortex as the airflow vortex changes direction and flowsdown into the air outlet passageway 29. The curved area of theappendages 17 interfaces with the vortex airflow going into the airoutlet passageway 29, maximizing the energy transfer from the airflowvortex to the particle accelerator assembly 16, thus maximizing theappendages' rotational velocity.

In the orientation shown in FIGS. 4, 6 and 7, the airflow management ofthis precleaner is clearly shown by controlling the direction of theairflow vortex through the upwardly angled air inlet vanes 34 over thedirectional strakes 61, into fluid communion with the particleaccelerator assembly 16, continuing through the circular toroidal domeseparator chamber 5, allowing a portion of the airflow and the debris toexit the air precleaner 1 through the debris ejection duct 25 withminimal turbulence while the clean airflow vortex changes direction 180degrees and increases velocity going through the air outlet passageway29, powering the particle accelerator assembly 16 with minimal energyloss due to the curved area of the appendages 17. The particleaccelerator assembly 16 maximizes the complete use of the swept-backappendages 52 by balancing the transfer of energy absorbed by the curvedarea of the appendages 17 that form a cupped shape when operating in theair outlet passageway 29 and transferring that energy to the incomingairflow vortex through the curved appendage's leading edge 3 andvertical appendage 19. The particle accelerator assembly 16 has manyfunctional components that all work together in one fluid motion withoutcreating airflow turbulence.

In the orientation shown in FIGS. 6 and 7, the airflow vortex enters thecircular toroidal dome separator chamber 5, flowing in an outwarddirectional circular pattern. The swept-back appendages 52 of theparticle accelerator assembly 16 contact the airflow vortex at the sameangle it leaves the upwardly angled air inlet vanes 34 and therefore arein fluid communion with the airflow vortex leaving the upwardly angledair inlet vanes 34. The swept-back appendages 52 are moving through theincoming airflow vector many times faster than the incoming airflowvector producing an outward velocity vector that greatly increases thecentrifugal force while directing the airflow vector outward to theinner wall 10 of the circular toroidal dome separator chamber 5 and outthe debris ejection duct 25.

In the orientation shown in FIGS. 1 and 5, the particle acceleratorassembly 16 has one top strake 22 and one bottom strake 23 mounted onthe top and bottom on the curved appendage's leading edge 3 of eachswept-back appendage 52 along the entire length of the swept-backappendage 52. FIG. 1A shows these strakes and an appendage in crosssection. These top and bottom strakes 22 and 23 offer structuralreinforcement and form entrapments for airborne debris, directing thedebris down the length of the swept-back appendage 52 and depositing thedebris in the airflow vortex circulating around the inner wall 10 of thecircular toroidal dome separator chamber 5. Additional verticalappendage strakes 24 are attached to the windward surface of thevertical appendage 19, forming several outward directional guides thatentrap and direct debris into the debris ejection duct 25. The leadingedge 21 of the vertical appendage 19 is contoured to match the inwardslope of the circular toroidal dome separator chamber 5 and align withan equal distance along the entire leading edge 21 of the verticalappendage 19 to the debris ejection duct 25.

In the orientation shown in FIGS. 1 and 5, the particle acceleratorassembly 16 has multiple swept-back appendages 52 mounted on a centralhub 36 that is rotatably attached to the circular toroidal domeseparator chamber 5 by a permanently affixed center shaft 11. Thisaffixed center shaft 11 extends upwardly into the center of the bearingassembly 14. The affixed center shaft 11 is attached to the bearingassembly 14 with a lock nut 12, tightened to result in the properbearing preload. The affixed center shaft 11 is machined down to form astep 39 that mates to the inner race of the lower bearing 14, allowingthe affixed center shaft 11 to extend through the bearing assembly 14and be secured by the top bearing inner race spacer 53 and lock nut 12in the upper shaft cavity 9. The central hub 36 forms a smoothtransition from the downward arch of the circular toroidal domeseparator chamber 5 to the bottom of the central hub 36, ending as around-tipped cone centered over the air outlet passageway 29. Thisallows for a smooth airflow transition around the central hub 36 intothe air outlet passageway 29. A labyrinth seal to prevent air and debrisfrom entering the bearing cavity 64 is formed by male labyrinth seal lip37 and female labyrinth seal lip 38.

In the orientation shown in FIGS. 1,6,8,9 and 10, the airflow vortexexits the air inlet passageway 2 and enters the lower section of thecircular toroidal dome separator chamber 5, moving through the particleaccelerator assembly 16. The inner wall 10 of the circular toroidal domeseparator chamber 5 is configured with three circumferential strakes 6,7 and 8. One strake 6 is located at the bottom, one strake 7 is locatedin the middle, and one strake 8 is located near the top of the circulartoroidal dome separator chamber 5. These circumferential strakes 6, 7and 8 trap debris and direct it to the debris ejection duct 25 whileminimizing any effect on the vortex airflow movement through thecircular toroidal dome separator chamber 5. The inner wall 10 of thecircular toroidal dome separator chamber 5 slopes inwardly decreasingthe open area 55 of the circular toroidal dome separator chamber 5,which causes the vortex airflow to increase velocity. The vortex airflowmoves through the circular toroidal dome separator chamber 5 in acyclonic pattern moving upwardly along the inner wall 10, making severalrevolutions around before reaching the circular toroidal arch 62,folding over, and whirlpooling down past the bearing cavity support 63,powering the particle accelerator assembly 16, and exiting through theair outlet passageway 29.

In the orientation shown in FIGS. 1, 6, 8 and 11, the circular toroidaldome separator chamber 5 is configured to direct the vortex airflow paththrough a linear reduction in cross section area 59, which increases thevelocity of the vortex airflow in the open area 55 of the circulartoroidal dome separator chamber 5. The increase in velocity keeps thedebris circulating around the inner wall 10 of the circular toroidaldome separator chamber 5, allowing for several opportunities for thedebris to be ejected out of the debris ejection duct 25. The linearreduction in cross section area 59 also minimizes the turbulence andairflow restriction through the decreasing open area 55 of the circulartoroidal dome separator chamber 5.

In the orientation shown in FIGS. 1, 5, 8 and 11, the bearing cavity 64is formed in the bearing cavity support 63 centered in the downwardslope of the circular toroidal separator chamber 5 centered over the airoutlet passageway 29. The bearing assembly 14 is made of one lowerbearing seated in the bearing cavity 64 to affix the outer race andalign the affixed center shaft 11 and one spacer spring 15 to keep thebearing properly spaced but not allowing the bearing assembly 14 to beoverloaded, e.g. spacer spring 15 can be compressed by upward movementof the particle accelerator assembly 16 and shaft 11 in the bearingcavity 64 when the air precleaner is subjected to jarring or impactloading in a direction along the longitudinal axis C--C, the springabsorbing some of the shock and preventing the bearing assembly frombeing overloaded. Thus, this mounting arrangement acts as a shockabsorber for rotatably mounting the particle accelerator assembly 16.The bearing assembly 14 is seated in the top of the bearing cavity 64 bya bearing retainer ring 13 which is held in place by the bearingretainer screws 54 and a top bearing inner race spacer 53, goes onto theaffixed center shaft 11, and is held in place by a lock nut 12. An uppershaft cavity 9 holds the threaded portion of the affixed centered shaft11, bearing retainer ring 13 and bearing retainer screws 54, top bearinginner race spacer 53, and lock nut 12. The upper shaft cavity 9 issealed with a top shaft cavity seal 60.

In the orientation shown in FIGS. 1, 6, 9 and 10, the debris ejectionduct 25 is formed into the vertical side of the circular toroidal domeseparator chamber 5 at the bottom 56 and extends vertically to top 57.The debris ejection duct opening 27 is larger at the bottom 56 anddecreases in open area to its smallest point at the top 57. The leadingedge 26 of the debris ejection duct 25 extends into the outermost areaof the airflow vortex 58 while the circular toroidal dome separatorchamber outer housing edge ends at 28, along the entire length of thedebris ejection duct opening 27. The debris ejection duct 25 isconfigured to eject debris and a minimal amount of vortex air from thecircular toroidal dome separator chamber 5. The debris ejection ductopening 27 is positioned near normal to the vortex airflow allowing forseveral opportunities for debris to be ejected while the vortex airflowpasses over the ejection outlet duct multiple times.

In the orientation shown in FIGS. 1, 2, 3, 7, 8 and 11, the airflowvortex has reached its maximum velocity as it flows over the leadingedge chamfer 31, powers the particle accelerator assembly 16, flowsthrough the air outlet passageway 29, and exits the air precleaner 1.

The above described precleaner of the present invention offers a meansof precleaning air that makes maximum use of centrifugal force whileminimizing airflow restriction. The airflow management of thisprecleaner 1 is clearly shown by the above described invention to allowfor maximum debris separation out of the vortex airflow whilemaintaining a fluid communion between the air and the precleaner. Afurther benefit derived from the airflow management of this airprecleaner 1 is its ability to operate over a broad airflow range,producing a very flat performance curve resulting in high debrisefficiency removal rates throughout the entire airflow range. FIG. 12illustrates the results of tests of an embodiment of the invention whichdemonstrate a very high rate of particulate removal over a broad airflowrange of the air precleaner used in connection with an internalcombustion engine. Precleaner efficiency as plotted in FIG. 12 wasdetermined by calculating the percentage of dust and debris exiting theprecleaner's debris ejection duct based on the total mass of dust anddebris injected into the precleaner.

All references to "TOP" or "BOTTOM" and corresponding identifying labelsto the air precleaner 1 have been used herein for illustrative purposesin as much as the air precleaner 1 can be mounted and function in anyposition. The air precleaner in the disclosed embodiment is made ofmolded plastic components except for the center shaft of the particleaccelerator assembly and the bearings and spring rotatably supportingthe assembly, which are made of metal. However, the invention is notconfined to the particular construction and specific arrangement ofparts herein illustrated and described, but embraces such modified formsthereof as come within the scope of the following claims.

I claim:
 1. An air precleaner for centrifugally ejectingheavier-than-air particulate debris from an air stream drawn through theair precleaner for use in an apparatus having an air intake, said airprecleaner comprising: a base, a circular separator chamber connected tosaid base and including an inner wall with a debris ejection ducttherein; and a particle accelerator assembly rotatably mounted in saidseparator chamber; said base having an inlet for the passage of debrisladen air into said air precleaner, a plurality of air inlet vanesangled upwardly with respect to a longitudinal axis of said airprecleaner for directing incoming debris laden air into said circularseparator chamber as a vortex airflow and an outlet for the passage ofair from said air precleaner after the air has moved through saidcircular separator chamber for centrifugally removing heavier-than-airparticulate debris therefrom by way of said debris ejection duct; andsaid circular separator chamber being formed with a toroidal dome forsmooth airflow transition of the vortex airflow moving through saidseparator chamber in a cyclonic pattern upwardly from said inlet pastsaid debris ejection duct where it is folded over by said toroidal domefor whirlpooling down to said outlet radially inwardly of and throughsaid upwardly moving vortex airflow, said particle accelerator assemblyincluding a central hub having an outer configuration which forms asmooth transition from a downward arch of said toroidal dome to thebottom of said central hub.
 2. The air precleaner according to claim 1,wherein said downward arch of said toroidal dome is formed by a circulartoroidal arch at an upper end of said separator chamber.
 3. The airprecleaner according to claim 2, wherein said inner wall of saidseparator chamber, as seen in a cross section thereof taken along saidlongitudinal axis of said air precleaner slopes inwardly in thedirection of said toroidal dome to decrease the cross sectional area forsaid vortex airflow moving through said separator chamber.
 4. The airprecleaner according to claim 3, wherein the shape of said separatorchamber provides a linear reduction in cross sectional area of the flowpath for said vortex airflow moving through said separator chamberthereby increasing the velocity of the vortex airflow in the separatorchamber and keeping debris in the air circulating around said inner wallof the separator chamber for ejection through said debris ejection duct.5. The air precleaner according to claim 1, wherein said debris ejectionduct extends upwardly along an inner wall of said separator chamberbetween said air inlet and said toroidal dome.
 6. The air precleaneraccording to claim 5, wherein the open area of said debris ejection ductis larger at a lower end of said duct than at an upper end thereof anddecreases from said lower end to said upper end.
 7. The air precleaneraccording to claim 1, wherein said particle accelerator assembly furtherincludes a plurality of curved appendages that arc back from saidcentral hub in a swept-back attitude relative to the direction of thevortex airflow coming off said upwardly angled air inlet vanes therebyimparting an outward velocity vector to the air and debris.
 8. The airprecleaner according to claim 7, wherein a curved area of the appendagesextends downward into a passageway of said air outlet of said base, saidcurved area being cupped in the direction of the airflow vortex in saidair outlet passage for rotationally powering said particle acceleratorassembly at a speed greater than the rotational speed of said upwardlymoving vortex airflow.
 9. An air precleaner for centrifugally ejectingheavier-than-air particulate debris from an air stream drawn through theair precleaner for use in an apparatus having an air intake, said airprecleaner comprising:a base, a circular separator chamber connected tosaid base and including an inner wall with a debris ejection ducttherein; and a particle accelerator assembly rotatably mounted in saidseparator chamber; said base having an inlet for the passage of debrisladen air into said air precleaner, a plurality of air inlet vanesangled upwardly with respect to a longitudinal axis of said airprecleaner for directing incoming debris laden air into said circularseparator chamber as a vortex airflow and an outlet for the passage ofair from said air precleaner after the air has moved through saidcircular separator chamber for centrifugally removing heavier-than-airparticulate debris therefrom by way of said debris ejection duct; andsaid circular separator chamber being formed with a toroidal dome forsmooth airflow transition of the vortex airflow moving through saidseparator chamber in a cyclonic pattern upwardly from said inlet pastsaid debris ejection duct where it is folded over by said toroidal domefor whirlpooling down to said outlet radially inwardly of and throughsaid upwardly moving vortex airflow, wherein said debris ejection ductextends upwardly in an inner wall of said circular separator chamber, aplurality of circumferential strakes being provided on said inner wallof said separator chamber for trapping debris moving in said vortexairflow and directing the debris to the debris ejection duct.
 10. An airprecleaner for centrifugally ejecting heavier-than-air particulatedebris from an air stream drawn through the air precleaner for use in anapparatus having an air intake, said air precleaner comprising:a base, acircular separator chamber connected to said base and including an innerwall with a debris ejection duct therein; and a particle acceleratorassembly rotatably mounted in said separator chamber; said base havingan inlet for the passage of debris laden air into said air precleaner, aplurality of air inlet vanes angled upwardly with respect to alongitudinal axis of said air precleaner for directing incoming debrisladen air into said circular separator chamber as a vortex airflow andan outlet for the passage of air from said air precleaner after the airhas moved through said circular separator chamber for centrifugallyremoving heavier-than-air particulate debris therefrom by way of saiddebris ejection duct; and said circular separator chamber being formedwith a toroidal dome for smooth airflow transition of the vortex airflowmoving through said separator chamber in a cyclonic pattern upwardlyfrom said inlet past said debris ejection duct where it is folded overby said toroidal dome for whirlpooling down to said outlet radiallyinwardly of and through said upwardly moving vortex airflow, whereinsaid particle accelerator assembly includes a central hub and a centershaft connected to said central hub, said particle accelerator assemblybeing rotatably mounted in said separator chamber by way of said centershaft which is rotatably supported by a bearing assembly, in an upperend of said separator chamber, said central hub having an outerconfiguration which forms a smooth transition from a downward arch ofsaid circular toroidal dome of said separator chamber to the bottom ofsaid central hub, which ends as a rounded tipped cone centered over saidair outlet in said base.
 11. The air precleaner according to claim 10,wherein a labyrinth seal is provided between adjacent ends of saidcentral hub of said particle accelerator assembly and said downward archof said circular toroidal dome of said separator chamber in the vicinityof said smooth transition from said downward arch to said central hub.12. An air precleaner for centrifugally ejecting heavier-than-airparticulate debris from an air stream drawn through the air precleanerfor use in an apparatus having an air intake, said air precleanercomprising:a base, a circular separator chamber connected to said baseand including an inner wall with a debris ejection duct therein; and aparticle accelerator assembly rotatably mounted in said separatorchamber; said base having an inlet for the passage of debris laden airinto said air precleaner, a plurality of air inlet vanes angled upwardlywith respect to a longitudinal axis of said air precleaner for directingincoming debris laden air into said circular separator chamber as avortex airflow and an outlet for the passage of air from said airprecleaner after the air has moved through said circular separatorchamber for centrifugally removing heavier-than-air particulate debristherefrom by way of said debris ejection duct; and said circularseparator chamber being formed with a toroidal dome for smooth airflowtransition of the vortex airflow moving through said separator chamberin a cyclonic pattern upwardly from said inlet past said debris ejectionduct where it is folded over by said toroidal dome for whirlpooling downto said outlet radially inwardly of and through said upwardly movingvortex airflow, wherein said particle accelerator assembly includes acentral hub and a plurality of appendages curved as an arc extendingfrom said central hub in a swept-back attitude relative to the directionof said vortex airflow coming off said upwardly angled air inlet vanes,said appendages each having strakes formed into the top and bottom of aleading edge thereof for entrapment of airborne debris, directing thedebris down the length of the appendage and depositing the debris in theairflow vortex circulating around said inner wall of said circulartoroidal dome separator chamber.
 13. The air precleaner according toclaim 12, wherein the radially outer ends of said appendages extendvertically and are contoured to match an inward slope of said circulartoroidal dome separator chamber with an equal distance along the entireleading edge of said vertically extending outer ends of said appendagesto the debris ejection duct, said vertically extending appendages beingwider at their bottom end and narrowing in the direction of their topend.
 14. The air precleaner according to claim 13, wherein saidvertically extending outer ends of said appendages each have a pluralityof outwardly directed strakes formed thereon for entrapping anddirecting debris into said debris ejection duct.
 15. The air precleaneraccording to claim 1, where each of said air inlet vanes is providedwith directional strakes in its bottom side for directing the debrisladen air as it passes over said air inlet vanes.
 16. An air precleanerfor centrifugally ejecting heavier-than-air particulate debris from anair stream drawn through the air precleaner for use in an apparatushaving an air intake, said air precleaner comprising: a base; a circularseparator chamber connected to said base and including an inner wallwith a debris ejection duct therein; and a particle accelerator assemblyrotatably mounted in said separator chamber; said base having an inletfor the passage of debris laden air into said air precleaner, aplurality of air inlet vanes angled upwardly with respect to alongitudinal axis of said air precleaner for directing incoming debrisladen air into said circular separator chamber as a vortex airflow, saidinlet vanes being arranged in non-overlapping relation with respect toeach other as seen in a direction along said longitudinal axis of saidair precleaner and said inlet vanes being offset relative to saidlongitudinal axis, and an outlet for the passage of air from said airprecleaner after the air has moved through said circular separatorchamber for centrifugally removing heavier-than-air particulate debristherefrom by way of said debris ejection duct, and said particleaccelerator assembly including a central hub and a plurality of curvedappendages that arc back from said central hub in a swept-back attituderelative to the direction of the vortex airflow coming off said upwardlyangled air inlet vanes.
 17. An apparatus for centrifugally ejectingheavier-than-air particulate debris from an air stream drawn into theapparatus, said apparatus comprising: means forming a circular separatorchamber having an inner wall with a debris ejection duct therein; aparticle accelerator assembly rotatably mounted in said separatorchamber for rotation about a longitudinal axis of said apparatus; aninlet for the passage of debris laden air into said circular separatorchamber; a plurality of air inlet vanes angled upwardly with respect tosaid longitudinal axis of said apparatus for directing incoming debrisladen air into said circular separator chamber as a vortex airflow; anoutlet for the passage of air from said separator chamber after the airhas moved through said circular separator chamber for centrifugallyremoving heavier-than-air particulate debris therefrom by way of saiddebris ejection duct; said circular separator chamber being formed witha toroidal dome for smooth airflow transition of the vortex airflowmoving through said separator chamber in a cyclonic pattern upwardlyfrom said inlet past said debris ejection duct where it is folded overby said toroidal dome for whirlpooling down to said outlet radiallyinwardly of and through said upwardly moving vortex airflow; and whereinsaid inner wall of said separator chamber, as seen in a cross-sectionthereof taken along said longitudinal axis slopes inwardly in thedirection of said toroidal dome over most of the axial extent of saidinner wall to progressively decrease the cross-sectional area for saidvortex airflow moving through said separator chamber.
 18. An apparatusaccording to claim 17, wherein said debris ejection duct extendsupwardly along said inner wall of said separator chamber between saidair inlet and said toriodal dome.
 19. The apparatus according to claim18, wherein at least one circumferential strake is provided on saidinner wall of said separator chamber for trapping debris moving in saidvortex airflow and directing the debris to said debris ejection duct.20. The apparatus according to claim 17, wherein a leading edge of saiddebris ejection duct extends into the outer most area of the airflowvortex.
 21. The apparatus according to claim 17, further comprising ashock absorber mounting arrangement for rotatably mounting said particleaccelerator assembly for rotation in said separator chamber.